White Rodgers 1F90 User manual

Printed in U.S.A. PART NO. 37-5426A
9507
1F90 and 1F97
Addendum to
INSTALLATION INSTRUCTIONS
WHITE-RODGERS
R
WHITE-RODGERS DIVISION
EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123-5398
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.
PRECAUTIONS
Ifindoubtaboutwhetheryourwiringismillivolt,line,orlow
voltage, have it inspected by a qualified heating and air
conditioning contractor, electrician, or someone familiar
with basic electricity and wiring.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical
codes and ordinances.
To prevent electrical shock and/or equipment
damage,disconnectelectricpowertosystem,at
main fuse or circuit breaker box, until installa-
tion is complete.
Do not short out terminals on gas valve or pri-
marycontroltotest.Shortorincorrectwiringwill
burn out thermostat and could cause personal
injury and/or property damage.
CAUTION
!
INSTALLATION
WHENTHISTHERMOSTATISCONNECTEDTOSOME
SYSTEMSTHATUSEHIGHIMPEDANCEINPUTELEC-
TRONIC MODULES, YOU MAY OBSERVE THE FOL-
LOWING CONDITIONS.
1. Thefurnace fanmay turnon whenheat hasnot been
called,ormaynotturnoffwhenthermostatissatisfied
and call for heat ends.
2. The furnace may not turn off when thermostat is
satisfied and call for heat ends.
3. The air conditioner may not turn off when thermostat
is satisfied and call for cool ends.
Ifyouobserveanyoralloftheseconditionsafterinstalling
thermostat,youcancorrectsystemoperationbyinstalling
isolationrelaysbetweenthethermostatandtheelectronic
ignitionmodule.Figures1and2showhowthreeisolation
relayscanbeinstalled[oneeachforthefan(G),heat(W),
andcool(Y)].Youmaynotneedtoinstallallthreeisolation
relays to correct the operation conditions.
Transformer
Red Jumper Wire
THERMOSTAT
24 VAC
Line
Voltage
Figure 1. Wiring for single transformer systems
RH W Y G RC
Heating
System Cooling System Fan Relay
Figure 1 shows a single transformer heating/cooling sys-
tem, with isolation relays installed in the heating (W),
cooling (Y), and fan (G) circuits. To simplify the diagram,
limit and safety switches are not shown here, although
they will be found either in the low or high voltage circuit.
Limit and safety switches must be retained. Refer to the
equipment manufacturer’s system wiring diagram for the
location of limit and safety switches.
DONOTREMOVEOR WIRE AROUNDLIMITAND
SAFETY SWITCHES WHEN INSTALLING ISOLA-
TION RELAYS.
WARNING
!

INSTALLATION (cont’d)
Transformer
THERMOSTAT
24 VAC
Line
Voltage
Figure 2. Wiring for two-transformer systems
RH W Y G RC
Heating
System Cooling System Fan Relay Transformer
24 VAC Line
Voltage
Figure 2 shows a two-transformer heating/cooling sys-
tem, with isolation relays installed in the heating (W),
cooling (Y), and fan (G) circuits. To simplify the diagram,
limit and safety switches are not shown here, although
theyarefoundeitherintheloworhighvoltagecircuit.Limit
and safety switches must be retained. Refer to the
equipment manufacturer’s system wiring diagram for the
location of limit and safety switches.
WARNING
!
DONOTREMOVEORWIRE AROUND LIMIT AND
SAFETY SWITCHES WHEN INSTALLING ISOLA-
TION RELAYS.